Dennis O'Donnell shows the Shark Shield shark deterrent device at his Maui store, Hawaiian Island Surf and Sport, in Kahului, Hawaii on Dec. 20, 2013. A surge in shark attacks on Maui hasn’t stopped people from surfing and swimming in the warm ocean waters that surround this Hawaiian island. But it has spurred sales of devices that claim to keep sharks away by emitting an electric pulse. (AP Photo/Audrey McAvoy)

A surfer models a shark deterrent device, the Electronic Shark Defense System, in Honolulu on Dec. 17, 2013. A surge in shark attacks on Maui hasn’t stopped people from surfing and swimming in the warm ocean waters that surround this Hawaiian island. But it has spurred sales of devices that claim to keep sharks away by emitting an electric pulse. (AP Photo/Audrey McAvoy)

KIHEI, Hawaii (AP) — A surge in shark attacks on Maui over the past year, including two fatal ones, hasn't stopped people from surfing and swimming in the warm ocean waters that surround the Hawaii island.

But it has spurred sales of devices that claim to keep sharks away by emitting an electric pulse.

"They just cannot make these things fast enough," said Hawaiian Island Surf & Sport owner Dennis O'Donnell, who keeps a waiting list for the products and sells out as soon as he's restocked.

Users strap the devices to their ankles, wetsuits or surfboards. Some are about the size of an oversized watch, others the size of a wallet. They range in price from $399 to $649.

Some shark experts say the devices may help in some cases, but it's questionable whether they'll repel large sharks.

With or without the devices, people need to remember they are taking a risk when they go into waters inhabited by large predators like sharks, said George Burgess, the director of the Florida Program for Shark Research.

"It's not equal to going to the YMCA pool or the pool at the hotel," Burgess said.

The sales spike comes as there have been eight shark attacks in Maui waters last year. Statewide, there were 14 attacks in 2013. There were 11 attacks in Hawaii in 2012 and three the year before.

In August, a German tourist died a week after a shark bit off her arm. In December, a man fishing on his kayak died after a shark bit his foot that was dangling in the water.

The last time anybody was killed by a shark in Hawaii waters was in 2004.

Sterling Kaya, owner of the Honolulu fishing supply store Hana Pa'a Fishing Co., said he used a device once while using a spear to fish in the Marshall Islands.

Without it, sharks ate the catch he and his fellow fishermen strung to a float while they fished, Kaya said. But the sharks stayed away when they attached the device to their catch.

Carl Meyer, a shark researcher at the Hawaii Institute of Marine Biology, said the devices may reduce the risk of a shark bite but won't eliminate it, cautioning that no independent, peer-reviewed studies have been conducted on their effectiveness.

Burgess said the only people who would need one of the devices are those whose jobs put them regularly in direct contact with sharks. People who dive for abalone or sponges in places where sharks are very common might fall into this category, he said.

Spearfishermen may also benefit as they are diving with bloody fish that can attract sharks. But there's still a question of whether the electrical field released by the device will deter the fish they're trying to spear, Burgess said.

Burgess is also skeptical whether the devices will effectively deter large sharks that tend to be the types involved in fatal attacks on humans — like tiger, white or bull sharks.

Even so, he noted the odds of getting bitten by a shark are tiny. People are much more likely to drown or have a heart attack in the water than be attacked by a shark, he said.

Dan Peters, who visited Maui from Kirbyville, Texas, said hearing about the shark attacks concerned him, but it didn't stop him from going in the ocean.

"I know they're not out there specifically looking for me," he said.

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

*We welcome your comments on the stories and issues of the day and seek to provide a forum for the community to voice opinions. All comments are subject to moderator approval before being made visible on the website but are not edited. The use of profanity, obscene and vulgar language, hate speech, and racial slurs is strictly prohibited. Advertisements, promotions, and spam will also be rejected. Please read our terms of service for full guides